Wireless communication devices are commonly used today to wirelessly communicate information about goods. For example, transponders may be attached to goods during their manufacture, transport and/or distribution to provide information, such as the good's identification number, expiration date, date of manufacture or “born on” date, lot number, and the like. The transponder allows this information to be obtained unobtrusively using wireless communication without slowing down the manufacturing, transportation, and/or distribution process.
Some goods involve environmental factors that are critical to their manufacture and/or intended operation. An example of such a good is a vehicle tire. It may be desirable to place a wireless communication device in a tire so that information regarding the tire, such as a tire's identification, pressure, temperature, and other environmental information, can be wirelessly communicated to an interrogation reader during the tire's manufacture and/or use.
Tire pressure monitoring may be particularly important since the pressure in a tire governs its proper operation and safety in use. For example, too little pressure in a tire during its use can cause a tire to be damaged by the weight of a vehicle supported by the tire Too much pressure can cause a tire to rupture. Tire pressure must be tested during the manufacturing process to ensure that the tire meets intended design specifications. The tire pressure should also be within a certain pressure limits during use in order to avoid dangerous conditions. Knowledge of the tire pressure during the operation of a vehicle can be used to inform an operator and/or vehicle system that a tire has a dangerous pressure condition. The vehicle may indicate a pressure condition by generating an alarm or warning signal to the operator of the vehicle.
During the manufacturing process of a tire, the rubber material comprising the vehicle tire is violently stretched before taking final shape. Wireless communication devices placed inside tires during their manufacture must be able to withstand this stretching and compression and still be able to operate properly after the completion of the tire's manufacture. Since wireless communication devices are typically radio-frequency communication devices, an antenna must be coupled to the wireless communication device for communication. This antenna and wireless communication device combination may be placed in the inside of the tire along its inner wall or inside the rubber of the tire, for example. This results in stretching and compression of the wireless communication device and its antenna whenever the tire is stretched and compressed. Often, the antenna is stretched and subsequently damaged or broken, thereby either disconnecting the wireless communication device from an antenna or changing the length of the antenna, which changes the operating frequency of the antenna. In either case, the wireless communication device may be unable to communicate properly when the antenna is damaged or broken.
Therefore, an object of the present invention is to provide an antenna for a wireless communication device that can withstand a force, such as stretching or compression, and not be susceptible to damage or a break. In this manner, a high level of operability can be achieved with wireless communication devices coupled to antennas for applications where a force is placed on the antenna.